It has long been desirable to have a removable auxiliary lens assembly attached to eyeglasses. Professional baseball players have used “flip-up” auxiliary lenses for more than four decades to protect their eyes from the sun, but to allow them unrestricted vision in the event the ball was hit in their vicinity.
U.S. Pat. No. 3,252,747 to Robins discloses an eyewear system specifically designed for persons who are far sighted. The device includes an assembly in which an auxiliary frame assembly containing lenses may be rotated about the horizontal axis and remains attached to a primary assembly so as to locate the lenses the proper distance to the eyes every time the device is lowered into place. A significant disadvantage of this design is that it is unattractive, overly complicated, impossible to segregate from the primary frame, and does not permit or accommodate anyone other than far sighted individuals.
U.S. Pat. No. 6,089,708 to Ku discloses a connecting member having spaced connecting plates for attachment to the bridge portion of a primary lens assembly. The connecting plates have magnetic members that act cooperatively with a complimentary magnetic member inserted in a hole on the bridge. The front of the connecting part has an open communication to a polygonal shaped holding room. The auxiliary frame has connecting rods extending above the bridge portion, and supporting an intermediate portion having a polygonal shape, receivable and rotatable in the holding room. A significant disadvantage of this design is that it is unattractive, overly complicated, and resist easy and immediate removal of the auxiliary lens assembly.
U.S. Pat. No. 3,238,005 to Petitto discloses the combination of a primary lens assembly and auxiliary lens assembly. The auxiliary assembly has flexible side wall projections with openings that can be assembled onto lugs (pins) extending perpendicularly from the sides of the primary assembly, allowing the auxiliary assembly to be pivoted upwards, and back downwards. Leaf springs mounted on the auxiliary assembly engage surfaces of the primary assembly to urge the auxiliary assembly into position. A significant disadvantage of this design is that it is unattractive, overly complicated, and resist easy and immediate removal of the auxiliary lens assembly.
As stated, these and other mechanically clipped on devices for holding auxiliary lenses are cumbersome and unattractive. More recently, numerous attempts have been made to magnetically attach an auxiliary lens assembly to a primary lens assembly.
U.S. Pat. No. 5,416,537 to Sadler discloses a primary lens assembly having a first magnetic member attached vertically to the front surface of the primary lens assembly, and a second magnetic member attached in a corresponding position on the back surface on an auxiliary lens assembly. The magnetic members are arranged for engagement to attach the auxiliary lens assembly to the primary lens assembly. A disadvantage of this design is that it is unattractive, and fails to prevent disengagement when vertically jarred, as may occur when stepping off a curb, jumping, or jogging.
U.S. Pat. No. 5,568,207 to Chao also discloses a magnetically adhered auxiliary lens assembly, with the additional feature of arms extending from the side portions of the auxiliary lens assembly, over magnet retaining projections and extensions of the primary lens assembly. The arms engage with, and are supported on, the primary lens assembly extensions to prevent disengagement of the auxiliary lens assembly upon downward movement of the auxiliary lens assembly relative to the primary lens assembly.
A disadvantage of this design is that it requires at least some specific vertical path movement for lowering the auxiliary lens assembly into a precise positional alignment with a capture mechanism for securing the auxiliary lens assembly to the primary lens assembly. As a result, positioning and removal of the auxiliary lens assembly against the primary lens assembly is difficult, cumbersome, and inconvenient. Additionally, it relies of thin metal extension components from the auxiliary lens assembly.
It can thus be seen that there is a need to develop a design for a primary lens assembly in which the primary frame assembly can be adapted to accept an improved and simplified attachment of a complementary configured auxiliary lens assembly.